Wheel hub motor unit

Abstract

Wheel hub motor unit (1) comprising: a rim element (10) with a tire (15) attached along its outer circumference; a spoke (20) connected to the rim element (10) and rotated with the rim element (10); a motor part (40) arranged in a mounting space (30) formed by the rim element (10) and the spoke (20), configured to generate rotational force by supplying current and to rotate the spoke (20); a steering knuckle part (60) connected to the motor part (40) and configured to support a suspension part (32); and a hub part (70) which is attached on one side to the spoke (20) and is connected on the other side to the axle part (60) and is designed to rotatably support the spoke (20); wherein the motor part (40) comprises: a rotor element (42) which is attached to the spoke (20); a rotor (44) which is attached to the rotor element (42) and is magnetic;a stator (46) which is installed in a position facing the rotor (44) and is magnetic; and a motor housing (48) which is designed to support the stator (46) and which is connected to the axle journal part (60) and is prevented from rotating; characterized by a first fixing connecting element (50) which is designed to fix the rotor element (42) to the motor housing (48) and which is removed after the rotor element (42) has been attached to the spoke (20), or a second fixing connecting element (52) which is designed to fix the spoke (20) to the motor housing (48) and which is removed after the hub part (70) has been attached to the spoke (20).

Description

Cross-reference to related registrations The present application claims priority over Korean patent application No. 10-2019-0071391, filed on June 17, 2019, which is incorporated by reference into the subject matter of the present application. Background of the invention Area Exemplary embodiments of the present disclosure relate to a wheel hub motor unit and, in particular, a wheel hub motor unit in which a part belonging to a wheel hub motor does not impair a body part. Discussion of the background of the invention Because of the risk of fossil fuels becoming depleted, electric vehicles have been developed instead of vehicles that use fossil fuels such as gasoline and diesel; these vehicles power a motor using electrical energy stored in a battery. Electric vehicles are divided into purely electric vehicles, which operate a motor using only electrical energy stored in a rechargeable battery; solar cell vehicles, which operate a motor using a photoelectric cell; fuel cell vehicles, which operate a motor using a hydrogen fuel cell; and hybrid vehicles, which use both an internal combustion engine powered by fossil fuels and an electric motor powered by electricity. Generally, an in-wheel motor unit is used for a vehicle such as an electric vehicle, which uses electricity as a power source. Unlike a device that rotates wheels using force transmitted through the internal combustion engine, transmission, and driveshaft of a gasoline or diesel vehicle, the in-wheel motor unit transmits power directly to the wheels via electric motors located in left / right drive wheels or four left / right and front / rear drive wheels. The conventional wheel hub motor unit has the problem that a part belonging to the wheel hub motor unit protrudes into a wheel element and thus interferes with a body panel. Therefore, there is a need for a device suitable for solving this problem. The prior art is disclosed in Korean patent application KR 10 2011 0 040 459 A, published on April 20, 2011, entitled "Apparatus of Driving Wheels for In-Wheel System". DE 10 2006 002 421 A1 discloses a wheel hub motor unit with the features of the preamble of claim 1. US 2016 / 0 121 709 A1 discloses another wheel hub motor unit. Overview of the invention Numerous different embodiments relate to a wheel hub motor unit in which a part belonging to a wheel hub motor does not affect a body part. According to one embodiment, a wheel hub motor unit can comprise: a rim element with a tire mounted along its outer circumference; a spoke connected to the rim element and rotated with it; a motor part arranged in a mounting space formed by the rim element and the spoke, configured to generate rotational force and rotate the spoke by supplying current; a steering knuckle part connected to the motor part, configured to support a suspension part; and a hub part attached to the spoke on one side and connected to the steering knuckle part on the other side, configured to rotatably support the spoke. The spoke may have: a core element located in a position facing the hub part; and an extension element extending radially from the core element and connected to the circumference of the rim element. The motor part comprises: a rotor element attached to the spoke; a rotor attached to the rotor element and magnetic; a stator installed in a position facing the rotor and magnetic; and a motor housing designed to support the stator and connected to the axle part and prevented from rotating. The wheel hub motor unit further comprises a first fixing connecting element designed to fix the rotor element to the motor housing, and which is removed after the rotor element has been attached to the spoke. The wheel hub motor unit also has a second fixing connecting element designed to fix the spoke to the motor housing, which is removed after the hub part has been attached to the spoke. The hub part may have: an inner hub race that is connected to the spoke and rotates with the spoke; and an outer hub race that is arranged outside the inner hub race with the insertion of a hub bearing, and that is connected to the axle part and prevented from rotating. The wheel hub motor unit may further comprise: a resolver installed at a position facing the inner hub race and configured to measure the position of the inner hub race; and an inverter configured to receive the measured value from the resolver and installed in the motor part. The wheel hub motor unit may also include a brake component located in the motor component, designed to inhibit the rotation of the spoke in accordance with a control signal. The brake part may include: a disc element that is attached to the spoke and rotated with the spoke; and a brake caliper that is located in the motor part and is moved in one direction to contact the disc element to generate a braking force. According to the embodiments described in the present disclosure, the motor part is located in the wheel element formed from the rim element and the spoke, and the brake part and the hub part are located in the motor part. It is therefore possible to increase the degree of design freedom, while the suspension part does not interfere with the wheel hub motor unit. Brief description of the drawings Fig. 1 is a perspective view illustrating a wheel hub motor unit according to an embodiment of the present disclosure. Fig. 2 is a rear view illustrating the wheel hub motor unit according to the embodiment of the present disclosure. Fig. 3 is a cross-sectional view illustrating the wheel hub motor unit according to the embodiment of the present disclosure. Fig. 4 is a cross-sectional exploded view illustrating main components of the wheel hub motor unit according to the embodiment of the present disclosure. Fig. 5 is a cross-sectional view showing that a motor part is spaced apart from a spoke according to an embodiment of the present disclosure. Fig. 6 is a cross-sectional view showing that a first fixing connection element has been released after the motor part has been connected to the spoke according to the embodiment of the present disclosure.Figure 7 is a cross-sectional view schematically representing a wheel hub motor unit according to another embodiment of the present disclosure. Figure 8 is a cross-sectional exploded view showing main components of the wheel hub motor unit according to the embodiment of the present disclosure. Figure 9 is a cross-sectional view showing that a motor part, a spoke, and a rim element are separated from one another according to the embodiment of the present disclosure. Figure 10 is a cross-sectional view showing that the motor part, the spoke, and the rim element are connected to one another according to the embodiment of the present disclosure. Figure 11 is a cross-sectional view showing that a hub part is arranged at a position spaced apart from the spoke according to the embodiment of the present disclosure.Figure 12 is a cross-sectional view showing that a second fixing connecting element is released when the hub part is connected to the spoke according to the embodiment of the present disclosure. Detailed description of the illustrated exemplary embodiments The following describes a wheel hub motor unit with reference to the accompanying drawings, using various exemplary embodiments. It should be noted that the drawings are not to scale and that the thickness of lines or the size of components may be exaggerated for the sake of clarity and to simplify the description. Furthermore, the terms used herein are defined with regard to functions of the invention and may be modified according to the customs or purposes of users or operators. Therefore, the definitions of the terms should be based on the present complete disclosure. Fig. 1 is a perspective view illustrating a wheel hub motor unit according to an embodiment of the present disclosure, Fig. 2 is a rear view illustrating the wheel hub motor unit according to the embodiment of the present disclosure, Fig. 3 is a cross-sectional view illustrating the wheel hub motor unit according to the embodiment of the present disclosure, Fig. 4 is a cross-sectional exploded view illustrating main components of the wheel hub motor unit according to the embodiment of the present disclosure, Fig. 5 is a cross-sectional view showing that a motor part is spaced apart from a spoke according to an embodiment of the present disclosure, and Fig. 6 is a cross-sectional view showing that a first fixing connection element has been released after the motor part has been connected to the spoke according to the embodiment of the present disclosure. As shown in Figures 1, 2, 3, 4, 5 to 6, a wheel hub motor unit 1 according to the embodiment of the present disclosure comprises a rim element 10, a spoke 20, a motor part 40, a steering knuckle part 60, and a hub part 70. The rim element 10 has a tire 15 mounted along its outer circumference. The spoke 20 is connected to the rim element 10 and rotates with it. The motor part 40 is located in a mounting space 30 formed by the rim element 10 and the spoke 20, and rotates the spoke 20 using torque generated by an electric current. The steering knuckle part 60 is connected to the motor part 40 and supports a suspension part 32. One side of the hub part 70 is attached to the spoke 20 and the other side is connected to the steering knuckle part 60, and the hub part 70 rotatably supports the spoke 20.The wheel hub motor unit 1 also includes a coordinate converter 80, an inverter 85, a brake part 90 and a first fixing connecting element 50. The tire 15 is mounted along the outer circumference of the rim element 10. The rim element 10 is mounted circumferentially, supporting the tire 15. The spoke 20 can be modified in various shapes, as long as the spoke 20 is connected to the rim element 10 and rotated with the rim element 10. The spoke 20 according to the embodiment of the present disclosure has a core element 22 which is attached at a position facing the hub part 70, and an extension part 24 which extends radially from the core element 22 and is connected to the circumference of the rim element 10. The spoke 20 and the rim element 10 can be designed as a single body. Alternatively, the spoke 20 and the rim element 10 can be designed as separate elements and connected to each other by a fastening device. This means that the spoke 20 and the rim element 10 can be modified in various ways. The core element 22 is mounted on the central axis C of the wheel hub motor unit 1 and is connected to the hub part 70 and rotates with an inner hub race 72. The extension part 24 extends in a spoke shape and is connected to the rim element 10. The spoke 20 is connected to one side (the right side in Fig. 3) of the rim element 10 and extends in a top-to-bottom direction. Therefore, the spoke 20 and the rim element 10 can be integrated and connected by a separate fastening bolt. This means that the spoke 20 and the rim element 10 can be modified into various shapes. The rim element 10 and the spoke 20 have a U-shaped longitudinal section and form the mounting space 30 on the inside for the installation of the motor part 40, the hub part 70 and the brake part 90. The suspension component 32 is attached to the steering knuckle component 60 of the wheel hub motor unit 1. The suspension component 32 comprises a lower arm 33, an upper arm 34, a trailing arm 36, and a damper 37. Since the structures and operating conditions of the respective components are generally known, a detailed description of them is omitted here. The motor part 40 is arranged in the mounting space 30, which is formed by the rim element 10 and the spoke 20, and various types of drive devices can be used as the motor part 40, as long as the spoke 20 is rotated by a torque generated by an electric current. The motor part 40 according to the embodiment of the present disclosure comprises a rotor element 42, a rotor 44, a stator 46, and a motor housing 48. The rotor element 42 is installed in such a way that it faces the rim element 10 and the spoke 20, and is attached to the spoke 20 and rotates with the spoke 20. According to the embodiment described in the present disclosure, the rotor element 42 has a U-shaped longitudinal section and is attached to a side surface of the spoke 20 by means of a fastening bolt 100 or a fastening element. The rotor 44 is attached to the rotor element 43, is magnetically attached to it, and is rotated with the rotor element 42. According to the embodiment described in this disclosure, a permanent magnet is used as the rotor 44. The rotor 44 is arranged in a ring shape along the inside of the rotor element 42. The stator 46 is mounted at a position facing the rotor 44 and is magnetically attached. The motor housing 48 supports the stator 46 and is connected to the axle journal 60, preventing it from rotating. This motor housing 48 is located inside the rotor element 42 and is mounted circumferentially. The stator 46 is arranged along the outer circumference of the motor housing 48, and the motor housing 48 has a hollow section formed within it. The stator 46, which is an electromagnet, generates magnetism in response to a control signal. The rotor 44, located at a position facing the stator 46, is rotated according to a change in the magnetism of the stator 46. If the motor part 40 is a three-phase motor, the stator 46 can have a U-phase coil, a V-phase coil and a W-phase coil. Various types of fastening devices can be used as the first fixing connecting element 50, as long as the fastening devices fix the rotor element 42 to the motor housing 48 and are removed after the rotor element 42 is attached to the spoke 20. According to the embodiment of the present invention, the first fixing connecting element 50 has a pin or bolt shape and is guided horizontally through the rotor element 42 so that it can be attached to the side surface of the motor housing 48. Since the motor housing 48 and the rotor element 42 can be temporarily assembled and moved together, the time and costs required for the assembly process can be reduced. The steering knuckle 60 can be designed in various shapes, as long as it can directly support the weight of a wheel, including the tire 15, the rim element 10, and the spoke 20. The steering knuckle 60 is connected to the motor housing 48 and an outer hub race 74 and prevents the motor housing 48 and the outer hub race 74 from rotating. Furthermore, the steering knuckle 60 is connected to the suspension element 32 to support the suspension element 32 and supports a load transmitted to the rim element 10 and the spoke 20. The hub part 70 can be designed in various forms, as long as the hub part 70 is attached at one side to the pivot axis C of the spoke 20 and at the other side to the axle stub part 60, and rotatably supports the spoke 20. The hub part 70 according to the embodiment of the present disclosure comprises the inner hub race 72, the outer hub race 74, and a hub bearing 76. The inner bearing race 72 is attached to the inner surface of the rotor element 42, and the rotor element 42 is attached to the inner surface of the spoke 20. Therefore, the inner bearing race 72 is connected to the spoke 20 and rotates with it. The inner bearing race 72 extends horizontally, and the inner bearing race 72, a disc element 92 of the brake part 90, the rotor element 42, and the spoke 20 can be connected to each other by attaching fasteners, including the fastening bolt 100 and a fastening nut 102, and rotated together. The hub bearing 76 is mounted on the outside of the inner hub race 72 and thus reduces friction that occurs when the inner hub race 72 rotates. The outer hub race 74 is located outside the inner hub race 72, with the hub bearing 76 interposed, and is connected to the steering knuckle part 60 and prevented from rotating. The coordinate converter 80 is mounted at a position facing the inner hub race 72 and measures the position of the inner hub race 72. According to the embodiment of the present disclosure, the coordinate converter 80 is located in the outer hub race 74 and transmits position information for motor control to the inverter 85, which serves as the control unit. The coordinate transducer 80, attached to the outer hub race 74, is a sensor for measuring the position of the rotor 44 of the motor part 40. Since the coordinate transducer 80 has greater mechanical strength and durability than an encoder, it is used as a motor position sensor in various fields such as electric vehicles, robots, aircraft, and military equipment that require high-performance and high-precision operation. The inverter 85 receives the measured value from the coordinate converter 80 and is installed in the motor part 40. According to the embodiment described in this disclosure, the inverter 85 can be arranged in a space formed by the motor housing 48 and the rotor element 42, and is installed circumferentially. Various types of brake devices can be used as the brake element 90, as long as the brake element 90 is arranged in the motor part 40 and inhibits the rotation of the spoke according to a control signal. The brake element 90 according to the embodiment of the present disclosure comprises the disc element 92 and a brake caliper 94. The disc element 92 can be modified into various shapes, as long as the disc element 92 is attached to the spoke 20 and rotated with the spoke 20. According to the embodiment described in the present disclosure, the disc element 92 is fastened between the inner hub race 72 and the rotor element 42 and is rotated with the rotor element 42. The fastening element, arranged horizontally through the inner hub race 72, is successively passed through the disc element 92, the rotor element 42, and the spoke 20, and then attached outside the spoke 20. Therefore, the inner hub race 72, the disc element 92, the rotor element 42, and the spoke 20 are rotated together. The brake caliper 94, located in the motor part 40, is installed in a part secured against rotation, such as the motor housing or the steering knuckle part 60. The brake caliper 94 is actuated according to a control signal and is moved in one direction in contact with the disc element 92, thereby generating a braking force. Therefore, a disc brake device can be installed in the wheel hub motor unit 1 without modifying the front or rear wheel suspensions. The assembly and operating conditions of the wheel hub motor unit 1 according to the embodiment of the present disclosure are described in more detail below with reference to the associated drawings. As shown in Fig. 4, the stator 46 is attached to the outside of the motor housing 48 and the inverter 85 is attached to the inside of the motor housing 48. The rotor 44 is then installed along the inner circumference of the rotor element 42, facing the stator 46. The motor housing 48 and the rotor element 42 are fastened by means of the first fixing connecting element 50 and the rotation of the rotor element 42 is temporarily blocked. The steering knuckle part 60 for supporting the suspension part 32 is connected to the motor housing 48 and blocks the movement of the motor housing 48. Since the steering knuckle part 60 is connected to the outer hub race 74, the rotation of the outer hub race 74 is also blocked. As shown in Fig. 5, when the inner hub race 72, the disk element 92 and the rotor element 42 are arranged successively, the fastening bolt 100 guided through the inner hub race 72 is successively guided through the disk element 92 and the rotor element 42, so that the inner hub race 72, the disk element 92 and the rotor element 42 are temporarily assembled. As shown in Fig. 6, the fastening nut 102 is connected to the fastening bolt 100 projecting outwards from the rotor element 42, with the spoke 20 bearing against the side surface of the rotor element 42. Thus, the inner hub race 72, the disc element 92, the rotor element 42, and the spoke 20 are rotated together. Once the rotor element 42 is fully connected to the spoke 20, the first fixing connecting element 50, which is intended to block the rotation of the rotor element 42, is removed. This allows the rotor element 42 to rotate. The assembly process can be modified in various ways. For example, the rotor element 42 and the inner hub race 72 can be fastened by a separate fastening bolt before the spoke 20 is mounted. Afterwards, the first fixing connecting element 50 can be removed and the spoke 20 can be mounted in the usual way. When the wheel hub motor unit 1 is actuated, the rotor 44 is moved according to a change in the magnetic flux of the stator 46 and is rotated with the rotor element 42. Since the disc element 92, the spoke 20 and the inner hub race 72 are rotated together by the rotation of the rotor element 42, the tire 15 is also rotated. Furthermore, the following describes a process in which a load generated by the road is transferred to a vehicle body via the wheel hub motor unit 1. A load generated on the road while a vehicle is traveling is transferred to the inner hub race 72 via the rim element 10 and the spoke 20. A force transmitted from the hub bearing 76, which faces the inner hub race 72, to the outer hub race 74 is transferred via the steering knuckle 60 to the suspension element 32 in such a way that vibrations are dampened and then transmitted to the vehicle body. A wheel hub motor unit 1 according to another embodiment of the present disclosure is described below with reference to the drawings. To simplify the description, components that are designed and operated in the same way as those of the previously described embodiment are provided with the same reference numerals, and a detailed description of them is omitted here. Fig. 7 is a cross-sectional view schematically representing a wheel hub motor unit according to another embodiment of the present disclosure; Fig. 8 is a cross-sectional exploded view showing main components of the wheel hub motor unit according to the embodiment of the present disclosure; Fig. 9 is a cross-sectional view showing that a motor part, a spoke, and a rim element are separated from each other according to the embodiment of the present disclosure; Fig. 10 is a cross-sectional view showing that the motor part, the spoke, and the rim element are connected to each other according to the embodiment of the present disclosure; Fig. 11 is a cross-sectional view showing that a hub part is arranged at a position spaced apart from the spoke according to the embodiment of the present disclosure; and Fig.Figure 12 is a cross-sectional view showing that a second fixing connecting element is released when the hub part is connected to the spoke according to the embodiment of the present disclosure. As shown in Figs. 7, 8, 9, 10, 11 to 12, the wheel hub motor unit 3 according to the embodiment of the present disclosure may require space in the axial direction of a motor part 41 to multiply the torque, thereby implementing a system that uses the spoke 20 like a rotor. The wheel hub motor unit 3 according to the embodiment of the present disclosure has parts that are actuated and designed in the same way as those of the wheel hub motor unit 1 according to the previously described embodiment, with the exception of the shape of a rotor element 43. Therefore, a detailed description of the other parts, with the exception of the rotor element 43, is omitted here. The motor part 41 according to the embodiment of the present disclosure comprises the rotor element 43 attached to the side surface of the spoke 20. The rotor element 43 is attached to the side surface of the spoke and has an L-shaped longitudinal section. The motor element 43 is installed at a position facing the motor housing 48, which has an L-shaped longitudinal section, and the stator 46 and the rotor 44 are installed in a space formed between the rotor element 43 and the motor housing 48. A bearing is installed between the rotor element 43 and the motor housing 48 to facilitate the rotation of the rotor element 43. A second fixing connecting element 52, which is contained in the wheel hub motor unit 3, fixes the spoke 20 to the motor housing 48 and is removed after the hub part 70 and the disc element 92 are attached to the spoke 20. The assembly of the wheel hub motor unit 3 according to the embodiment of the present disclosure is described in more detail below with reference to the associated drawings. As shown in Figures 8 and 9, the stator 46 is attached to the outside of the motor housing and the inverter 85 is attached to the inside of the motor housing 48. The rotor 44 is then moved along the inner circumference of the rotor element 43 towards the stator 46. Finally, as shown in Figure 10, the rotor element 43 is brought into contact with the side surface of the spoke 20 and fastened to the spoke 20 by means of a fastening element. The motor housing 48 and the spoke 20 are connected to each other by the second fixing connecting element 52 and the rotation of the spoke 20 is temporarily blocked. As shown in Fig. 11, the axle stub part 60, which supports the suspension part 32, is connected to the outer hub race 74, and the fastening bolt 100, guided through the inner hub race 72, is arranged through the disc element 92. As shown in Fig. 12, the fastening bolt 100, guided through the disc element 92, protrudes outwards from the spoke 20 and is secured by means of the fastening nut 102, thereby bringing the disc element 92 into contact with the side surface of the spoke 20. Therefore, the inner hub race 72, the disc element 92, and the spoke 20 rotate together. Since the steering knuckle 60 is also attached to the motor housing 48, the motor housing 48 and the outer hub race 74 are prevented from rotating. After the rotor element 43 has been fully connected to the spoke 20, the second fixing connecting element 52 is removed to block the rotation of the spoke 20. This allows the spoke 20 to rotate. According to the embodiments described in the present disclosure, the motor part 40 or 41 is located in the wheel element formed by the rim element 10 and the spoke 20. The brake part 90 and the hub part 70 are located within the motor part 40 or 41. Therefore, it is possible to increase the degree of design freedom, while the suspension part 32 does not interfere with the wheel hub motor unit 1 or 3.

Claims

Wheel hub motor unit (1) comprising: a rim element (10) with a tire (15) attached along its outer circumference; a spoke (20) connected to the rim element (10) and rotated with the rim element (10); a motor part (40) arranged in a mounting space (30) formed by the rim element (10) and the spoke (20), configured to generate rotational force by supplying current and to rotate the spoke (20); a steering knuckle part (60) connected to the motor part (40) and configured to support a suspension part (32); and a hub part (70) which is attached on one side to the spoke (20) and is connected on the other side to the axle part (60) and is designed to rotatably support the spoke (20); wherein the motor part (40) comprises: a rotor element (42) which is attached to the spoke (20); a rotor (44) which is attached to the rotor element (42) and is magnetic;a stator (46) which is installed in a position facing the rotor (44) and is magnetic; and a motor housing (48) which is designed to support the stator (46) and which is connected to the axle journal part (60) and is prevented from rotating; characterized by a first fixing connecting element (50) which is designed to fix the rotor element (42) to the motor housing (48) and which is removed after the rotor element (42) has been attached to the spoke (20), or a second fixing connecting element (52) which is designed to fix the spoke (20) to the motor housing (48) and which is removed after the hub part (70) has been attached to the spoke (20). Wheel hub motor unit (1) according to claim 1, wherein the spoke (20) comprises: a core element (22) arranged at a position facing the hub part (70); and an extension element (24) extending radially from the core element (22) and connected to the circumference of the rim element (10). Wheel hub motor unit (1) according to claim 1, wherein the hub part (70) comprises: an inner hub race ring (72) which is connected to the spoke (20) and rotates with the spoke (20); and an outer hub race ring (74) which is arranged outside the inner hub race ring (72) with an intermediate hub bearing (76), and which is connected to the axle stub part (60) and is prevented from rotating. Wheel hub motor unit (1) according to claim 3, further comprising: a coordinate converter (80) which is installed at a position facing the inner hub race (72) and which is configured to measure the position of the inner hub race (72); and an inverter (85) which is configured to receive the measured value of the coordinate converter (80) and which is installed in the motor part (40). Wheel hub motor unit (1) according to claim 1, further comprising a brake part (90) which is arranged in the motor part (40) and which is designed to inhibit the rotation of the spoke (20) according to a control signal. Wheel hub motor unit (1) according to claim 5, wherein the brake part (90) comprises: a disc element (92) which is attached to the spoke (20) and is rotated with the spoke (20); and a brake caliper (94) which is arranged in the motor part (40) and is moved in one direction to bear against the disc element (92) to generate a braking force.

Images